Abstract: The circular array of 200 equally angularly spaced marks about the surface of the rotating calibration disk of a watt-hour meter is optically sensed to provide a series of meter pulses indicative of the rate at which power is being consumed. Each meter pulse corresponds to 1/200 of the amount of the watts rating of the watt-hour meter as represented by one revolution of its disk. These small wattage meter pulses are converted into high frequency pulses and applied onto the household a.c. supply lines. A portable display unit plugged into any outlet of the a.c. supply lines is tuned to receive the high frequency pulses and feed them as digital meter pulses to a single chip microprocessor.

Abstract: A circuit and a computer program for enabling the monitoring of a plurality of switch settings at remote sites by central telephone exchange equipment through regular telephone lines is described. To compensate for slow drift variations in line impedance, the impedance of each line is continually calculated from the measurements, and any small change is used to update a line impedance correction factor, while any large instantaneous change is used to update the data counter. Telephone exchange battery variations which may be large and instantaneous, are compensated for by measuring the battery voltage immediately prior to measuring the line impedances, and correcting the line impedance readings with a battery voltage correction factor. Other types of temporary signal interference which are frequently present in telephone switching equipment are identified and rejected by applying consistency criteria to multiple readings which have been corrected by the aforementioned method.